3-year average adjusted bases percentage

(i) the aggregate adjusted bases (as determined for purposes of computing earnings and profits) of property (other than sales of foreclosure property or sales to which section 1033 applies) sold during the 3 taxable year period ending with such taxable year, divided by

(ii) the sum of the aggregate adjusted bases (as so determined) of all of the assets of the trust as of the beginning of each of the 3 taxable years which are part of the period referred to in clause (i).